Multiple sclerosis associated with amyotrophic lateral sclerosis: An unfortunate coincidence or a plausible concurrence?

Background: Multiple Sclerosis’ (MS) disease-modifying therapy (DMT) have allowed a longer life expectancy, so patients are at higher risk of having a neurodegenerative disorder. Muscular atrophy can happen in MS, but can also indicate other entities. Case report: We report a 52-year-old woman with relapse-remitting MS since 1999, with a recent rapidly clinical deterioration, presenting with progressive bulbar dysfunction, generalized muscular atrophy and upper motor neuron signs, in the absence of new demyelinating lesions. Neurophysiological investigation confirmed the diagnosis of amyotrophic lateral sclerosis. Conclusions: We herein discuss this association and other mimicking disorders, highlighting that a progressive bulbar palsy in ambulatory MS patients should be carefully evaluated.